JPH0122257B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the asymmetric N-phenyl-N The present invention relates to a method for producing '-substituted paraphenylene diamine. The reductive alkylation of nitroso compounds by reaction with aldehydes or ketones in the presence of hydrogen and hydrogenation catalysts has already been described.
It is publicly known. In this case, specific metal compounds such as copper chromite (British patent no.
804113, Soviet Union Patent No. 230828), nickel sulfide (West German Patent Application No. 1542171), selenides, tellurides or nickel-chromium catalysts (Ciechoslovakia Patent No. 119336) or heavy metals iron, manganese,
Mixtures of two or more of copper, chromium, nickel, silver, cerium and lead in the form of oxides, hydroxides or carbonates (DE 1941009) were used. however,
All these known catalysts act on side reactions, in particular the reduction of aldehydes or ketones to the corresponding alcohols. According to the process known from GB 1295672, p-nitroso-
Diphenylhydroxylamine is reacted with hydrogen and an aldehyde or ketone in the presence of a hydrogenation catalyst at temperatures ranging from room temperature to 200°C. Metals from groups of the Periodic Table, such as nickel, cobalt, ruthenium, palladium and platinum, are used as hydrogenation catalysts, if desired supported on inert supports, such as carbon, aluminum oxide or silica gel. Indeed, in this method, N-phenyl-
The yields of N'-alkyl- and N-phenyl-N'-cycloalkyl-p-phenylenediamines are approximately 95% of the theoretical value, which has not been achieved until now for the industrial production of this product. Yield and selectivity are still insufficient. Furthermore, too high catalyst amounts are required, which also results in considerable catalyst losses. The object of the present invention is to reductively alkylate p-nitroso-diphenylhydroxylamines with aldehydes or ketones in the presence of hydrogen and palladium or platinum sulfide on carbon and optionally in the presence of an inert solvent. This is a method for producing asymmetric N-phenyl-N'-substituted p-phenylenediamine by
- in an amount of not more than 1% by weight of palladium or platinum sulfide, based on nitrosodiphenylhydroxylamine, and by using as cocatalyst activated carbon with a specific surface area of at least 700 m ² /g and an ash content of not more than 7.5%; . p-Nitroso-diphenylhydroxylamine is a compound readily available by catalytic dimerization of nitrosobenzoles. According to a new and particularly advantageous process, when using as catalyst a sulfonic acid with a pka value below 1, such as methane-, ethane- or trifluoromethanesulfonic acid or perchloric acid or trifluoroacetic acid, practically no This can be achieved in quantitative yields (West German patent application
p2703919 specification). The nitrosobenzoles required for the preparation of p-nitroso-diphenylhydroxylamine are likewise readily available and are obtained by catalytic reduction of nitrobenzole. The reduction likewise proceeds in a novel manner with high conversions and high selectivities when using aliphatic, cycloaliphatic, olefinic or aromatic hydrocarbons as reducing agents (West German Patent Application No. 2713602). Specification). The compounds obtainable according to the invention contain in each case one phenyl group as a substituent on the N-atom and, on the contrary, one or two aliphatic, cycloaliphatic or aromatic substituents on the N′-atom. In this case, in the latter case, the substituents may be the same or different.
The choice of aldehyde or ketone for use is
Of course, it depends on the desired p-phenylenediamine derivative. For the production of N-phenyl-N'-monosubstituted p-phenylenediamine, aldehydes are
Ketones are used for the preparation of N-phenyl-N'-disubstituted p-phenylenediamines. Examples of suitable carbonyl compounds are aliphatic aldehydes, such as formaldehyde, alkyl-alkyl-
Ketones such as acetone, cyclic ketones such as cyclobutanone, aryl-aryl-ketones such as benzophenone, alkyl-aryl-ketones such as acetophenone and methylbenzylketone, alkyl-cycloalkyl-ketones,
For example, methylcyclohexylketone, aryl-cycloalkyl-ketones, such as phenylcyclohexylketone, aromatic aldehydes, such as benzaldehyde, cyclic aldehydes, such as cyclohexylaldehyde, as well as diketones,
For example, 2,4-pentanedione. The method of the present invention is applied to N-phenyl-N'-monoalkyl-p-phenylenediamine, N-phenyl-
Preference is given to using them for the preparation of N'-dialkyl-p-phenylenediamines and for the preparation of N-phenyl-N'-cycloalkyl-p-phenylenediamines. For this purpose, aldehydes, alkyl-alkyl-ketones or cyclic ketones are required. Examples of suitable aldehydes are formaldehyde,
These are acetaldehyde, propionaldehyde, butyraldehyde, and valeraldehyde. Examples of suitable alkyl-alkyl-ketones are acetone,
Methyl-ethyl-ketone, methyl-propyl-ketone, methyl-butyl-ketone, methyl-isobutyl-ketone, methyl-amyl-ketone, methyl-isoamyl-ketone, methyl-hexyl-ketone, methyl-heptyl-ketone, methyl- Octyl-ketone, diethyl-ketone, ethyl-propyl-ketone, ethyl-butyl-ketone, ethyl-ketone
These are amyl-ketone, ethyl-hexyl-ketone, ethyl-heptyl-ketone, 5-methyl-heptanone-(3), dipropyl ketone, dibutyl ketone, diisobutyl ketone, diamyl ketone, dihexyl ketone, diheptyl ketone, and diisodecyl ketone. Examples of suitable cyclic ketones are cyclobutanone, cyclopentanone, cyclohexanone and cyclooctanone. It is not absolutely necessary to use pure hydrogen; rather, a carrier gas, for example nitrogen, can also be used together. It is likewise possible to use gas mixtures which, in addition to hydrogen, also contain carbon monoxide, for example water gas or generator gas. In this case, carbon monoxide likewise takes part in the reduction; however, sufficient hydrogen must be present to ensure complete reduction. As hydrogenation catalysts, the customary palladium or platinum sulfides are used, ie catalysts with customary carbons as carriers, such as charcoal, soot and activated carbon. Platinum sulfide refers to commercially available "sulfurized platinum" obtained by sulfurizing platinum. Although the limited platinum sulfide is not important here, this type of catalyst is called platinum sulfide for industrial convenience (Robert I. Peterson, Hydrogenation
Catalysts, Noyes Data, Parkridge New
Jersey, USA, 1977, pp. 256-261). The type of support material is not very important, unlike the type of activated carbon added as a cocatalyst. However, it is advantageous to use activated carbon as support material as well, with a specific surface area of at least 700 m ² /g and an ash content of up to 7.5% by weight. The reductive alkylation of p-nitroso-diphenylhydroxylamine proceeds without any problems if, as in conventional processes, catalyst amounts having 1% or more of palladium or platinum sulfide, based on the starting materials, are used. However, such high catalyst amounts significantly increase the synthesis costs, and in particular the catalyst losses at high catalyst amounts are significant. Furthermore, in this case, the desired N-phenyl-
Large amounts of nuclear hydrogenation products are produced which are difficult to separate from the N'-substituted p-phenylenediamines.
Additionally, there is also a continuous hydrogenation of the excess carbonyl compound optionally used as a solvent to form the undesired alcohol (see Comparative Example). In contrast, in the process of the invention, the hydrogenation catalyst is preferably present in an amount corresponding to less than 1% by weight of palladium or platinum sulfide, based on the p-nitroso-diphenylhydroxylamine used. Palladium or platinum sulfide is used in an amount of 0.05 to 0.2% by weight relative to hydroxylamine. In this case, the formation of alcohol by hydrogenation of any excess carbonyl compound is completely suppressed. Similarly, under these conditions, nuclear hydrogenation of the desired N-phenyl-N'-substituted p-phenylenediamine also does not occur. A hydrogenation catalyst consisting of palladium or platinum sulfide and carbon carrier material is palladium or platinum sulfide.
It may contain 0.05 to 10% by weight. Advantageously,
The content of palladium or platinum sulfide is from 0.5 to 5% by weight, and it is particularly advantageous to use commercial noble metal/charcoal catalysts containing about 1 to 5% by weight of palladium or platinum sulfide. Therefore, the amount of hydrogenation catalyst for p-nitroso-diphenylhydroxylamine can be up to 0.1, depending on the respective noble metal content.
% by weight (for a 10% precious metal content) to 20% by weight (for a 0.05% precious metal content). Surprisingly, when activated carbon is used together with activated carbon as a catalyst according to the invention, both the selectivity and the yield of the reductive alkylation are significantly increased and the service life of this catalyst system in continuous processes is significantly increased. It became clear that. Strangely, this effect is only pronounced for palladium and platinum sulfide catalysts, and is hardly noticeable for other catalyst metals. The properties of activated carbon for use as a cocatalyst are:
This is the main feature of the present invention. It has been found that catalytic activity occurs only in highly activated carbons. The specific surface area of the activated carbon should be at least 700 m ² /g. The ash content of activated carbon is also important for the catalytic activity of activated carbon, which is 7.5% by weight
Must be less than or equal to Ash content refers to both insoluble and soluble ash components. Activated carbons obtained from natural starting materials, such as lignite, peat, wood, bone, etc., generally contain large amounts of ash and are therefore not suitable as such for use in the process of the invention. . However, by thorough washing with acid, the ash content can be reduced to 7.5
This is likewise taken into account when reducing the weight to below %, which has a specific surface area of the desired magnitude.
Trace elements have no or at most a low influence on the activity of the carbon catalyst. Therefore, the selection of a suitable carbon type depends on the two aforementioned criteria. Although all activated carbons with a specific surface area of 700 m ² /g or more and an ash content of 7.5% or less show activity in the method of the present invention, petroleum, natural gas,
Activated carbon made from coal or cellulose is advantageous because of its purity. Activated carbon to be used as cocatalyst according to the invention -
The amount of catalyst is from 10 to 200% by weight, based on the p-nitroso-diphenylhydroxylamine used.
This depends on the amount of noble metal relative to p-nitroso-diphenylhydroxylamine and on the noble metal content of the hydrogenation catalyst and the noble metal/support carbon ratio. In order to obtain similar yields, it is necessary to increase the amount of activated carbon-catalyst when lowering the amount of noble metal. There is a relationship between the precious metal content of the hydrogenation catalyst and the required amount of activated carbon catalyst:
Precious metals in the hydrogenation catalyst - content of approximately 1-10% by weight
, the amount of activated carbon catalyst required for similar conversions decreases with decreasing noble metal content. To achieve similar conversion rates, when the precious metal content ranges from about 0.05 to 1% by weight,
An increasing amount of activated carbon catalyst is required as the noble metal content decreases. In a preferred embodiment of the process according to the invention, the precious metal 0.05
0.01-20% by weight of palladium-carbon catalyst or platinum-sulfide-carbon catalyst with ~0.2% by weight and 10-200% by weight of activated carbon as cocatalyst are used. The amount of aldehyde or ketone is 1 to 1 per equivalent of p-nitroso-diphenylhydroxylamine.
10 equivalents, preferably 2 to 10 equivalents. It is also possible to use larger amounts of aldehyde or ketone, in which case the excess is used as solvent. If desired, other inert solvents (co-solvents),
For example aliphatic or aromatic hydrocarbons, their halogen derivatives or ethers, such as toluene, monochlorobenzole, dichlorobenzole, 1,
2,4-trichlorobenzole, or 1,1,2
-Trifluoro-1,1,2-trichloroethane can also be used. Particularly suitable inert solvents are lower alcohols such as methanol, ethanol, isopropanol, propanol, butanol, pentanol, isopentanol and 4-methylpentanol-2. The use of inert solvents is particularly advantageous if the water of reaction formed during the course of the reaction is insoluble or only slightly soluble in the ketone or aldehyde used, so that an aqueous phase forms in addition to the organic phase. It is. If the aldehyde or ketone is miscible with water to such an extent that no second phase is formed, it is advantageous not to additionally use a solvent. In the process of the invention it is also possible to use wet p-nitroso-diphenylhydroxylamine having up to 100% by weight of water. In this case, water likewise forms a co-solvent. p
It is not necessary that the -nitroso-diphenylhydroxylamine be present in dissolved form, ie that the reaction be carried out in a homogeneous phase. It is advantageous to carry out the reaction in a heterogeneous phase. This has the advantage that the reaction volume is relatively small and the reaction mixture is easy to work up. The process according to the invention can be carried out both batchwise and continuously. The reaction temperature and reaction pressure are not critical. Although the process according to the invention can already be carried out at normal pressure and room temperature, because of the influence of pressure and temperature on the reaction rate it is advantageous to carry out it at elevated temperature and pressure. Preferably, it is carried out at a temperature range of 20 to 150°C. Favorable reaction temperature is 25-125
℃, especially 40-100℃. The hydrogen pressure may vary over a wide range, for example from 1 to 150 bar. advantageously 5~
15 bar, especially 7 to 12 bar. The reaction time is generally between 15 minutes and 5 hours, preferably between 0.5 and 3 hours. Work-up of the reaction mixture is carried out in a customary manner. First, the catalyst is separated off, the solvent is optionally distilled off, and the amine is subsequently distilled or crystallized. The respective preferred method depends on the physical properties of the amine and the solvent used. The catalyst can be circulated. In conventional methods, the catalyst has partially lost its activity after the reductive alkylation carried out. Upon reuse, it exhibits a reduced activity, so that in practice it must be supplemented with a certain amount of fresh catalyst. On the other hand, in the case of the method of the present invention, the hydrogenation catalyst used retains its activity significantly by adding an activated carbon catalyst, and when it is further used, a completely fresh hydrogenation catalyst is added in order to obtain the original activity. It may be omitted or only added in relatively small amounts.
For example, during reductive alkylation according to the method of the present invention, palladium is added to p-nitroso-diphenylhydroxylamine in the first reaction cycle.
Using a catalyst with 0.2% by weight, reaction cycle number 2 requires only a further 0.01% by weight of palladium, based on p-nitroso-diphenylhydroxylamine, in addition to the hydrogenation catalyst used. Furthermore, after several reaction cycles, only a small amount of fresh catalyst addition is required for similar catalyst activity.
It decreases to 0.005% by weight. Finally, more reaction cycles can be carried out without the addition of fresh hydrogenation catalyst. With each new reaction cycle,
It is only necessary to introduce a new activated carbon catalyst. Therefore, on average, the amount of hydrogenation catalyst used per reaction cycle is less than 0.01% by weight of palladium, based on the p-nitroso-diphenylhydroxylamine used. For example, in the case of methyl isobutyl ketone, if in the first reaction cycle a catalyst with 0.2% by weight of platinum sulfide and 100% by weight of activated carbon is used for p-nitroso-diphenylhydroxylamine, the catalyst system loses no activity. A further 15 reaction cycles can be carried out without further addition. When this same series is run without activated carbon, the yield of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (DBPPD) in the first cycle is only 60% of the theoretical value.
% (whereas in the presence of activated carbon,
95% of theory), already in the second cycle it drops to 38% of theory (in contrast, in the presence of activated carbon, the yield is 95% of theory and unchanged). The method according to the invention has significant advantages over GB 1295672. According to Example 1 of the British patent specification, for example N-isopropyl-N'-
Phenyl-p-phenylenediamine (IPPD) is obtained with a yield of 93%. However, here we are not actually talking about the true yield of the desired substituted p-phenylenediamine, but rather the amount of reaction product remaining after distillation of the solvent, which incorrectly consists only of the desired material. It was regarded as such. As will become clear when working with this example, a quantitative conversion of the starting material does take place, however, the reaction product is N-isopropyl-N'-phenyl-
Only about 78 p-phenylenediamine (IPPD)
It is a substance mixture having a proportion of %. Furthermore, this requires a high amount of palladium, 0.3% by weight, based on p-nitrosodiphenylhydroxylamine, and long reaction times, and, moreover, it is necessary to work at a pressure of 50 bar. Due to this, N-
As isopropyl-N′-phenyl-p-phenylenediamine (IPPD) is subsequently hydrogenated to N-isopropyl-N′-cyclohexyl-p-phenylenediamine (ICPPD),
Not only is a large loss of IPPD obtained, but also a continuous reduction of excess ketones to undesired alcohols. In contrast, the present invention requires low pressures and low temperatures, small amounts of noble metal catalysts and significantly shorter reaction times; furthermore, the selectivity for the formation of the desired substituted p-phenylene diamines is significantly higher and the carbonyl compounds No formation of alcohol by reduction of . British Patent Specifications at lower temperatures, e.g. below 150°C, and at lower pressures, e.g.
When carried out below 50 bar, the reaction proceeds with significantly lower selectivity than under more aggressive conditions. In other words, the by-products at this time are about 25-50% of the reduction product that is not alkylated and about 2.5-10% of ketimine.
is obtained. The yield of the desired substituted p-phenylenediamine is only 12-70%, the remainder consisting of the unsubstituted starting compound and the above-mentioned by-products. Therefore,
The process of the invention is advantageous in that it is carried out at relatively low temperatures and pressures, uses very low amounts of precious metals, and leads to the desired products with short reaction times, high conversions and high selectivities. There is. The compound obtained by the method of the present invention is industrially required in large quantities as a rubber antioxidant or rubber antiozonant. Examples 1 to 9 (Comparative Examples) The reactions were carried out in a 1-glass autoclave equipped with a bottom outflow valve, a gas inlet pipe, a fluidized crusher and a propeller stirrer (magnetic stirring). p
- Nitroso-diphenylhydroxylamine (NDHA) 20g (93.2mMol) and acetone 200ml
It was used. The reaction was carried out between 30 and 75°C, the hydrogen pressure was between 9 and 10 bar, the reaction time was 1 hour, and the stirring speed was 1500 rpm. First, the autoclave was evacuated and then flushed with hydrogen.
The autoclave is then charged with half of the reaction medium and finally p-nitroso-diphenylhydroxylamine (NDHA) is suspended in the remainder of the reaction medium together with the palladium/charcoal catalyst and the inlet valve is closed. Added via. 9-10 bar of hydrogen was then pressurized into the autoclave and carefully heated. Depending on the amount of palladium, the reaction started between 20 and 70°C. After the heat of reaction had subsided, further heating was carried out to 75° C., and the total reaction time was 1 hour. Table 1 below shows the influence of the amount of noble metal on the yield of N-isopropyl-N'-phenyl-P-phenylenediamine (IPPD). The composition of the palladium/charcoal catalyst, the amount of metal relative to the p-nitroso-diphenylhydroxylamine used and the asymmetric N
The yield of -phenyl-N'-substituted p-phenylenediamine and the amounts of ketimine and alkylated p-phenylenediamine derivatives formed as by-products are listed together in Table 1. The following abbreviations are used in the table: NDHA = p-nitroso-diphenylhydroxylamine ADA = 4-amino-diphenylamine IPPD = N-isopropyl-N'-phenyl-P-
Phenylenediamine ketimine = N-isopropylidene-N'-phenyl-P-phenylenediamine

[Table] The results of this comparative experiment show that palladium 1
When using catalyst amounts corresponding to % by weight, the reductive alkylation still takes place with relatively high selectivity and yields the desired N-isopropyl-N'-phenyl-
It clearly shows that it becomes p-phenylenediamine. In contrast, when using small amounts of catalyst, the selectivity for the formation of N-isopropyl-N'-phenyl-p-phenylenediamine decreases rapidly. At a catalyst amount of 0.20% by weight of palladium,
It is already significantly lower than 10%. Examples 10 to 21 The increase in conversion and selectivity achieved according to the process according to the invention by the addition of activated carbon with a surface area of at least 700 m ² /g and an ash content of up to 7.5% by weight is evident from the examples and comparative examples in Table 2. can be known. For this purpose, Comparative Example 7 in Table 1
was repeated with and without the addition of activated carbon, and the conversion and yield were determined quantitatively after different reaction times. 60 g (280 mmol) of p-nitroso-diphenylhydroxylamine (NDHA) and 600 ml of acetone were each mixed into a palladium-charcoal catalyst (with a palladium content of 1.01% by weight, a specific surface area of 1100 m ² /g, and an ash content of 0.5% by weight or less). Degussa E10R)
The reaction was carried out as described in Examples 1-9 in the presence of 6.0 g. For example, in the case of Examples 17, 19 and 21, the yield of N-isopropyl-N'-phenyl-p-phenylenediamine is lower than in Example 15, because of the longer reaction time. Part of the already desired product is further reduced to N-isopropyl-
This is because it became N'-cyclohexyl-p-phenylenediamine.

[Table] Examples 22-32 A 1.5 glass autoclave equipped with a propeller stirrer, a thermometer, a gas inlet pipe, a pressure gauge, a fluidized crusher, an exhaust valve, a bottom exhaust valve and a filter cylinder was first charged with p-nitrosate. 20 g of diphenylhydroxylamine and a palladium/charcoal catalyst with a palladium content of 5% (manufactured by Degussa,
E10R) suspension consisting of 0.8 g p-nitrosodiphenylhydroxylamine (Pd 0.20%) and activated carbon (manufactured by Merck & Co., powder, dry, specific surface area 1050 m ² /g, ash content not more than 5% by weight) 25 g and 200 ml of methyl isobutyl ketone were charged. After a number of evacuations and venting with hydrogen, the reaction was started at a hydrogen pressure of 9-10 bar. The reductive alkylation was initiated at approximately 40°C and after cooling of the exothermic reaction was maintained at 75°C for a total of 1 hour with a stirring speed of 1500 rpm.
After the end of the reaction, the substrate was separated from the hydrogenation catalyst and activated carbon catalyst by means of a filter cylinder under hydrogen pressure and subsequently washed back into the autoclave with methyl isobutyl ketone. Then the next charge (20 g of p-nitroso-diphenylhydroxylamine and a total of methyl isobutyl ketone)
200 g) with activated carbon-catalyst and optionally fresh hydrogenation catalyst, again at 75-80 °C.
The reaction was then carried out for 1 hour at a hydrogen pressure of 9-10 bar. This experiment was carried out over 10 times in total, so that at the end of the reaction a total of 220 g of p-nitroso-diphenylhydroxylamine had been reductively alkylated. The amount of hydrogenation catalyst (expressed in % by weight of palladium based on the total amount of p-nitroso-diphenylhydroxylamine used) and the amount of activated carbon catalyst, as well as the amount of N-
(1,3-dimethylbutyl)-N'-phenyl-p
The obtained yields of -phenylenediamine (DBPPD), p-amino-diphenylamine (ADA) and ketimine are listed in Table 3 below. The results clearly show that after a small number of reaction cycles, the amount of freshly added hydrogenation catalyst and activated carbon is significantly reduced.

TABLE Examples 33-45 The following examples and comparative examples illustrate the influence of the amount of activated carbon used (Examples 33-36) and the type of activated carbon (Examples 37-45) on the course of the reductive alkylation. The reactions were carried out as described in Examples 1-9. 20 g of p-nitroso-diphenylhydroxylamine (NDHA) and 150 ml of methyl isobutyl ketone (MIBK) were used respectively. A palladium-charcoal catalyst (E106R manufactured by Degussa) with a palladium content of 1.02% by weight was used as the hydrogenation catalyst. As activated carbon, synthetic activated carbons from Degussa or Merck with different specific surface areas and ash contents as well as various activated carbons from natural raw materials were used. Comparative Examples 42 to 45 show that N-
(1,3-dimethylbutyl)-N'-phenyl-p
- It clearly shows that the yield of phenylenediamine (DBPPD) is lower.

【table】

[Table] N′-substitution P
- It retains its activity well in the presence of phenylenediamine (final product), so that when the same is used further, no or only a relatively small amount of fresh hydrogenation catalyst is added, and the original This indicates that it has regained its activity. Furthermore,
The resulting water of reaction is completely insoluble or only slightly soluble in the ketone used in the reductive alkylation,
Additional, inert solvents (co-solvents) have a beneficial effect in those cases in which a second aqueous phase would be formed without the addition of co-solvents. The reaction was carried out in the 1.5-apparatus already described in Examples 22-32. Reaction temperature is 75-100℃, hydrogen pressure is 9
~10 bar, reaction time 1.5 h, stirring speed
It was 1000-1500r.pm. After each cycle, a small sample is taken for analytical determination of the reaction mixture and then each p-nitroso-diphenylhydroxylamine (NDHA)
A subsequent charge consisting of 10 g, cyclohexanone and 50 ml each of cosolvent, and in each experiment an additional amount of activated carbon catalyst or fresh palladium on charcoal catalyst, was added via the inlet valve into the already reacted reaction mixture under H ₂ -pressure. It was introduced in If this experiment is performed more than 10 times in total, p-nitroso-diphenylhydroxylamine (NDHA) is produced at the end of the reaction.
A total of 100 g underwent reductive alkylation with cyclohexanone.

【table】

[Table] CPPD=N-phenyl-N'-cyclohexyl-p
-Phenylenediamine Example 56 (Comparative example) Follow-up experiment to Example 1 of British Patent No. 1295672 50 g of p-nitroso-diphenylhydroxylamine (NDHA) and 5 g of 3% palladium on activated carbon
(E10R, Degussa: equivalent to 0.3% Pd for NDHA), along with an anchor stirrer, gas introduction pipe, pressure gauge,
Suspended in 790 ml of acetone in a 2-stainless steel autoclave equipped with an overpressure valve and a bottom drain valve. After completely removing traces of oxygen from the autoclave, the reaction was started by pressurizing 50 bar of hydrogen and heating to 60° C. (heating time 15 minutes).
After holding at 60℃ for 1 hour, increase the temperature to 150℃ within 30 minutes.
Increase to 95°C, then lower to 95°C (15 min), 95°C
It was held for 6 hours. Thereafter, the reactor was cooled and the contents were separated from the catalyst by filtration under hydrogen protective gas. After distilling off the solvent, a gray-brown solid substance
93.25% (based on desired N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD)) remained. The reaction mixture was analyzed quantitatively. It had the following composition: N-isopropyl-N'-phenyl-p-phenylenediamine 77.90% N-isopropyl-N'-cyclohexyl-p
-Phenylenediamine 6.95% 4-Amino-diphenylamine 2.10% N,N'-diisopropyl-p-phenylenediamine 0.96% N-phenyl-N,N'-diisopropyl-p
-phenylenediamine 0.95% N-phenyl-N'-diisopropyl-p-phenylenediamine 0.65% p-anilino-cyclohexanone 0.65% In addition, this mixture contains a polymeric compound consisting mainly of 4-isopropylamino-diphenylamine units 2.84 %. In particular, there are nuclear hydrogenated compounds which occur at high pressures and temperatures and are very difficult to separate from the desired N-isopropyl-N'-phenyl-p-phenylenediamine. Additionally, approximately 18% of the acetone used was converted to isopropanol. Examples 57-68 20 g p-nitroso-diphenylhydroxylamine (NDHA) as described in Examples 1-9.
(93.2mMol) of methyl isobutyl ketone (MIBK) and platinum sulfide catalyst (Degussa)
F103RS, platinum sulfide - content 5% by weight) at a maximum temperature of 100 DEG C. and a hydrogen pressure of 9-10 bar.
The stirring speed was 1500 rpm. Reaction time is 45 minutes. Activated carbon has a specific surface area of 1050 m ² /g and ash content.
0.6% (activated carbon “pure” manufactured by Merck & Co.). After cooling to 40-50°C, the autoclave was depressurized and separated from the catalyst and optionally activated carbon under slight nitrogen pressure. The conventional process parameters and the composition determined quantitatively by gas chromatography of the reaction mixture obtained are shown in Table 6 below.

【table】

Claims (1)

[Claims] 1. p-Nitroso-diphenylhydroxylamine is reductively treated with an aldehyde or ketone in the presence of hydrogen and palladium on carbon or platinum sulfide, and optionally in the presence of an inert solvent. In producing the asymmetric N-phenyl-N'-substituted p-phenylenediamine by alkylation, the hydrogenation catalyst is added in an amount of up to 1% by weight of palladium or platinum sulfide based on the p-nitroso-diphenylhydroxylamine used. and as a cocatalyst, having a specific surface area of at least 700 m ² /g and an ash content of
A process for producing asymmetric N-phenyl-N'-substituted p-phenylenediamine, characterized in that 7.5% by weight or less of activated carbon is used. 2 Palladium or platinum sulfide is used as a hydrogenation catalyst in an amount of 0.05 to 0.2% by weight based on p-nitroso-diphenylhydroxylamine,
A method according to claim 1. 3. Process according to claim 1 or 2, wherein the amount of activated carbon catalyst is 10 to 200% by weight, based on the p-nitroso-diphenylhydroxylamine used. 4 The amount of aldehyde or ketone is 2 to 1 equivalent of p-nitroso-diphenylhydroxylamine.
A method according to any one of claims 1 to 3, wherein the amount is 10 equivalents. 5. carrying out the reaction in the presence of an inert solvent;
A method according to any one of claims 1 to 4. 6. The method according to claim 5, wherein methanol, ethanol, isopropanol, propanol, butanol, pentanol, isopentanol or 4-methylpentanol-2 is used as the inert solvent. 7. Claims 1 to 6, wherein the reaction is carried out at a temperature of 25 to 125°C and a hydrogen pressure of 1 to 150 bar.
The method described in any one of the preceding paragraphs. 8. Claims 1 to 7, wherein the reaction is carried out at a temperature of 40 to 100°C and a hydrogen pressure of 7 to 12 bar.
The method described in any one of the preceding paragraphs.